The invention relates to a cellular phone and in particular to a cellular phone that can be utilized as an external storage device for an external electronic apparatus.
Cellular phones are widely used, and their functionality has increased dramatically in recent years. Advances in semiconductor technology have enabled cellular phones to perform a wide variety of tasks, facilitating daily activities. Cellular phones, for example, can be used to place calls, take photographs, access the Internet, send and receive email, check stock quotes and sports scores, and operate as a personal digital assistant (or PDA) and MP3 player.
Data required for performing the described tasks is difficult to input manually via a keyboard, and is generally downloaded through a telephone network or via a wireless connection. Downloading through a telephone network is time consuming and requires a connection fee. A typical wireless connection, however, does not provide enough bandwidth to effectively download a large amount of data, such as a large image or video file.
Additionally, as cellular phone functionality increases, memory capacity therein increases accordingly, as does the amount of data required for performing the described tasks.
According to a conventional method, the memory of a cellular phone can be used as an external storage device for a computer. For a computer, in order to communicate with a cellular phone and utilize the memory therein as an external storage device, vendor-provided software must be pre-installed in the computer.
FIG. 1 is a schematic view of a conventional computer utilizing a cellular phone as an external storage device. A cellular phone 150 is connected to a computer 100 via a USB cable 13. Both computer 100 and cellular phone 150 comprise hardware and software components, wherein the computer 100 comprises a hardware component 120 and a software component 110, and the cellular phone 150 comprises a hardware component 170 and a software component 160. The software component 110 comprises an application program 111, a vendor specific driver 113, and a USB host controller/driver 115. Typically, the application program 111 and vendor specific driver 113 are provided by a cellular phone manufacturer, and installed in the computer 100 by a user. In order to communicate with an external device via the USB cable 13, the hardware component 120 comprises a USB hardware 121 and a USB interface 123. In order to receive and transmit data via the USB cable 13, the hardware component 170 comprises USB device 171 and a USB interface 173, and the software component 160 comprises a USB driver 165 and a USB command parsing engine 164. The USB command parsing engine 164 parses a command submitted via the vendor-provided application program 111 and/or the vendor specific driver 113, and data stored in a memory 175 is retrieved and/or stored accordingly. Utilization of the data stored in the memory 175 is accomplished through a file system 167 and a memory driver 169. For example, the memory 175 of the cellular phone 150 is a non-volatile memory, and the memory driver 169 is a Flash driver.
Here, the file system is a mechanism for storing and organizing files and the data they contain to make it easy to find and access them. File systems may use a storage device and involve maintaining the physical location of the files, or they may be virtual and exist only as an access method for virtual data or for data over a network (e.g. NFS). More formally, a file system is a set of abstract data types that are implemented for the storage, hierarchical organization, manipulation, navigation, access, and retrieval of data.
In order to use the memory 175 of the cellular phone 150 as an external storage of the computer 100, application program 111 and vendor specific driver 113 must be installed. A command is submitted via the application program 111 and the vendor specific driver 113 to transmit and store data from the memory 175 of the cellular phone 150. The command is transferred to the cellular phone 150 via the USB driver 115, USB hardware 121, USB interface 123, and the USB cable 13. The command is then received by the USB interface 173, and transferred to the USB command parsing engine 164 via the USB device 171 and USB driver 165. The command is parsed by the USB command parsing engine 164 and transmitted to the file system 167. The file system 167 retrieves data from and/or stores data in the memory 175 according to the parsed command. The file system 167 used for managing data transfer between the computer 100 and cellular phone 150 can be used for data management while an incoming call is received by the cellular phone 150.
In the conventional method, the installation of the application program 111 and the vendor specific driver 113 is required, otherwise various phone features cannot operate simultaneously when the cellular phone is used as a storage device for a computer, which is inconvenient and limits the usefulness of the phone.